People often find themselves in situations where they need or desire information concerning a particular topic. These situations may relate either to work or to leisure activities, but the desired information usually is not readily at hand unless an appropriate book or other information source is available. Although the information may be available from various reference sources such as periodical publications, books, or databases accessible through computers, these sources are not readily portable and in many cases are relatively expensive to purchase and maintain.
Problems associated with providing a convenient source of information on a selected topic are even greater where the information source should be readily portable, that is, sufficiently compact in size and weight so that a person will want to carry it with him or her. Regular hardback bound books are out of the question in most cases, due to the weight and bulk of such books. Even paperback books, although somewhat more convenient to carry than their hardback counterparts, usually do not fit conveniently within a person's pockets, and must instead be carried in a knapsack or some other carrier borne by the individual. Moreover, the bulk and space requirements of conventional bookbinding reduce the amount of information each page can display, and add to the number of pages required for a given amount of information, a significant factor for a portable or easily-carried compendium of information. Moreover, the very nature of bound books makes these books relatively inconvenient or expensive to modify as the information on a few pages is changed from time to time, and the conventional loose leaf alternative to binding usually adds to the weight and physical bulk of a book.